From: Daniel Phillips <phillips@arcor.de>
To: root@chaos.analogic.com
Cc: Imran Badr <imran.badr@cavium.com>,
"'David S. Miller'" <davem@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: Calculating kernel logical address ..
Date: Mon, 9 Sep 2002 20:50:38 +0200 [thread overview]
Message-ID: <E17oTcN-0006sn-00@starship> (raw)
In-Reply-To: <Pine.LNX.3.95.1020909144217.18372A-100000@chaos.analogic.com>
On Monday 09 September 2002 20:43, Richard B. Johnson wrote:
> On Mon, 9 Sep 2002, Daniel Phillips wrote:
>
> > On Monday 09 September 2002 20:00, Richard B. Johnson wrote:
> > > For some reason, (claimed performance reasons) user-mode code
> > > has to be able to get data directly from hardware with no
> > > intervening copy operation. I think any claimed advantage goes
> > > away when you look at the overhead necessary for user-mode
> > > code to sleep before, and awaken after, the DMA operation but
> > > often marketing departments make those decisions.
> >
> > Pfft. Try turning off ide dma and see what happens.
>
> I know that DMA works, I'm talking about DMA direct-to-user
> which is not what the file-systems that use DMA do.
The next generation of fast, parallel filesystems relies on dma
to/from user space. Besides, what do you think happens when you
read/write a mmap?
--
Daniel
next prev parent reply other threads:[~2002-09-09 19:04 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-09 17:06 Imran Badr
2002-09-09 17:29 ` Richard B. Johnson
2002-09-09 17:23 ` David S. Miller
2002-09-09 17:34 ` Martin J. Bligh
2002-09-09 17:40 ` Daniel Phillips
2002-09-09 17:31 ` Imran Badr
2002-09-09 18:00 ` Richard B. Johnson
2002-09-09 18:12 ` Imran Badr
2002-09-09 18:27 ` Daniel Phillips
2002-09-09 18:41 ` Imran Badr
2002-09-09 21:55 ` Alan Cox
2002-09-09 22:52 ` Imran Badr
2002-09-09 23:09 ` Alan Cox
2002-09-09 18:13 ` Jesse Barnes
2002-09-09 18:25 ` Daniel Phillips
2002-09-09 19:40 ` Andrew Morton
2002-09-09 20:41 ` Daniel Phillips
2002-09-10 6:43 ` Jens Axboe
2002-09-10 7:12 ` Andrew Morton
2002-09-09 18:42 ` Andrew Morton
2002-09-10 7:03 ` Gerd Knorr
2002-09-09 18:16 ` Kurt Ferreira
2002-09-09 18:17 ` David S. Miller
2002-09-09 18:17 ` Daniel Phillips
2002-09-09 18:43 ` Richard B. Johnson
2002-09-09 18:50 ` Daniel Phillips [this message]
2002-09-09 18:57 ` Richard B. Johnson
2002-09-09 18:08 ` Andrew Morton
2002-09-09 18:23 ` Daniel Phillips
2002-09-09 18:49 ` Imran Badr
2002-09-09 18:46 ` David S. Miller
2002-09-09 19:06 ` Daniel Phillips
2002-09-09 19:14 ` Andrew Morton
2002-09-09 19:23 ` Imran Badr
-- strict thread matches above, loose matches on Subject: below --
2002-09-09 21:19 Manfred Spraul
2002-09-09 21:47 ` Andrew Morton
2002-09-10 17:01 ` Manfred Spraul
2002-09-09 21:02 Manfred Spraul
2002-09-09 21:07 ` Imran Badr
2002-09-06 15:44 Manfred Spraul
2002-09-06 17:13 ` Imran Badr
2002-09-07 1:57 ` Daniel Phillips
2002-09-06 3:23 side-by-side Re: BYTE Unix Benchmarks Version 3.6 Daniel Phillips
2002-09-06 3:34 ` Calculating kernel logical address Imran Badr
2002-09-07 1:44 ` Daniel Phillips
2002-09-08 0:01 ` David S. Miller
2002-09-08 18:44 ` Daniel Phillips
2002-09-09 5:00 ` David S. Miller
2002-09-09 5:17 ` Daniel Phillips
2002-09-09 5:28 ` David S. Miller
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